Membership 2 and WPGYM from codecanyon don't work together

Hey WPMUDEV! I have bought “WPGYM”. It is an gym management system that I am going to use for my clients. The problem is that I also need some kind of protection plugin. When I use WPGYM and Membership 2 at the same time I gets this debug message:

” of undefined constant WDEV_DEBUG – assumed ‘WDEV_DEBUG’ in /customers/a/0/9/ on line 143 Warning: Cannot modify header information – headers already sent by (output started at /customers/a/0/9/ in /customers/a/0/9/ on line 97″”

Should I try the other protection plugin that you have instead? or is there any way to get them work together?

Greetings, Marcus